Data may be stored in a variety of database paradigms. For example, a relational database may include one or more tables that are linked using a primary key (e.g., a column). A flat file database may be a character delineated file without explicit relationship links. Different management systems may be used to extract, transform, and load data (ETL) into a database. For example, a relational database management system may use structured query language (SQL) statements to retrieve data from the database.
Another type of database, a graph database may be used for related data. Nodes of the database may represent objects, edges may connect the nodes to indicate a relationship, and properties may indicate information about the edges and nodes. A triplestore (sometimes referred to a resource description framework (RDF) store) is a type of graph database often used for semantic data that conforms to the subject-predicate (or property)-object format.